/**
* Created by rd on 2017/5/4.
*/
// 引入CryptoJSvar 
Crypto = require('./cryptojs.js').Crypto;
var app = getApp();
function RdWXBizDataCrypt(appId, sessionKey) {  
this.appId = appId  
this.sessionKey = sessionKey
}
RdWXBizDataCrypt.prototype.decryptData = function (encryptedData, iv) {  
// base64 decode ：使用 CryptoJS 中 Crypto.util.base64ToBytes()进行 base64解码  
var encryptedData = Crypto.util.base64ToBytes(encryptedData)  
var key = Crypto.util.base64ToBytes(this.sessionKey);  
var iv = Crypto.util.base64ToBytes(iv);  
// 对称解密使用的算法为 AES-128-CBC，数据采用PKCS#7填充  
var mode = new Crypto.mode.CBC(Crypto.pad.pkcs7);  
try {    
// 解密    
var bytes = Crypto.AES.decrypt(encryptedData, key, {      
asBpytes: true,      
iv: iv,      
mode: mode    
});    
var decryptResult = JSON.parse(bytes);  
} catch (err) { 
   console.log(err)  
}  
if (decryptResult.watermark.appid !== this.appId) {    
console.log(err)  
}  
return decryptResult
}
module.exports = RdWXBizDataCrypt